In the slums of Soweto, Tsotsi (PRESLEY CHWENEYAGAE) and his gang -- volatile enforcer Butcher (ZENZO NGQOBE), follower Aap (KENNETH NKOSI) and intellectual Boston (MOTHUSI MAGANO) -- are petty thieves and drug dealers who scrounge to get by, but don't seem to have many cares in the world.
That changes after they murder a man on the subway and Boston begins to question their acts. That and his bringing up Tsotsi's past enrage the leader who beats Boston to a pulp and then runs off into the night. Things then become even more complicated when the young thug carjacks rich Pumla Dube (NAMBITHA MPUMLWANA) and shoots her in the process.
Speeding away, he discovers to his horror that the woman's infant is in the backseat. Prepared to abandon it but then having second thoughts, Tsotsi returns the child to his hovel where he quickly comes to the realization that he has no idea how to care for it. Accordingly, he confronts a mother who lives nearby, Miriam (TERRY PHETO), and makes her breastfeed the baby at gunpoint.
From that point on, and as Pumla's husband John (RAPULANA SEIPHEMO) worries about his severely injured wife and missing child, and Tsotsi's gang grows apart from him, the thug must decide what to do with his life.